Process of coating wood



" M. E. DUNLAP.

PROCESS OF COATING W000. APPLICATION FILED ov. 5. 191a.

1,329,381. I y 4 Pa tented Feb. 3,1920.

Inventor.

UNITED sTATEs PATENT 0mm.

' MATTHEW E. DUNLAP, or 'MAmsom-wI'sooNsIN', ASSIGNOR '10 UNITED STATES or AMERICA.

PROCESS OF COATING WOOD. I

Specification of Letters Patent.

latentedFeb. 3, 1920..

Application filed November 5, 1918. Serial No. 261,210.

To all whom it may concern:

Be it known that I, MATTHEW a citizenof the United States, residing at Madison, in the county of Dane and State of \Visconsin, have invented certain new and useful Improvements in Processes of Coating'Wood, of which the following is a specification.

My invention relates to methods or proc-- esses of coating or finishing articles and has special reference to such as'are applicableto aerial propellers and other devices made of wood.

It is well known that many experiments have been made in an attempt to procure coverings for aerial propellers, but so far these have not proven' satisfactory. The

coatings or finishings thus far made require;

an expensive apparatus, asin the casewhere metal 1S sprayed, or electrolytically deposited and even these coatings when applled are too heavy, do not'adhere well, and are torn loose bycentrifugal force when the propellers are in action. Other methods have also been formulated differin in scope from those mentioned above w ich have not been \reliable in regard to the exclusion of moisture.

One object of my invention is to provide a simple and effective process of coating or finishing articles whereby a metallic covering is produced which when applied becomes closely associated and intimately united with the article itself.

Another object of my invention is the provision of the process of coating which shall comprise a combination of definite steps which are adapted to cooperate in the production of a metallic covering possessing, many advantages over coatings produced by either or the steps taken alone.

The principal object is to provide a process of coating or finishingarticles and especially aerial propellers whereby a coating of metal leaf is applied which will be substantially moisture proof, intimately adhesive, and will constitute a coating which is lighter and cheaper than those hitherto used, and also well able to resist adverse atmospheric conditions:

lVith these and other objectsin view the invention consists in certain novel features which will more fully'appear as the descrip- E.- DUNtAr,

tion proceeds, the novel features thereof being pointed out in the appended claims.

Referring tothe drawings which show the preferred embodiments .ofmy invention:

Figure 1 is a side elevationof a propeller blade to which the coating is applied.

Fig. 2 illustrates the completion of the process with the metal leaf afiixed about the varnished surface ofv the propeller, the addi-.

tional coat of varnish applied about themetal surface, and the intermediate steps shownv therebetween.

-As disclosed intthe drawing a propeller blade 4 is to be coated withmy covering. In

the process of coating a filler 5 ofv the standard type is first applied to the wooden blade and after this step one or more coats .of varnish 6, depending on the character of the wood as best'shown in Fig. 2, are next affixed. Ample time being allowed for the varnished surface to dry, at sanding process is next begun whereby the varnished surface is sanded until smooth. The operation of the coating as thus' far advanced has filled all the pin holes and inequalities in the exposed surface, thus presenting a suitable ground for the application of the metallic covering. The surface after being sanded is coated with a varnish which is used as a size. This coating 7 is allowed to partially dry until a proper tack is reached (by the term tack as used-here is meant the condition of the surface covered with varnish when it is not too dry to prevent metal leaf being applied thereto.)

Metal leaf or foil 8 such as aluminum or imitation gold, which is employed 'in this process, as a moisture excluding element and which is the principal ingredient of the im proved coating, tacky surface. applied either in a seriesof wrappings, or in leaf form.

Approximately six hours after the metal leaf has been applied the metal surface is is now applied to the coated with a liquid composition 9, prefer-'- It is to be understood. howably varnish. ever, that the composition appliedthereon is .not to be limited to varnish as lacquer or enamel may be successfully employed.

This metal leaf may be To complete the formation of the moisture proof coating one-or more coats of the abovo coating has been applied it is very difiieult to disturb the coating and separate it from the articlecovered. Exhaustive tests have likewise shown, first, that the metal leaf applied about wooden articles has the ability to resist adverse atmospheric conditions,

and second, that the metal leaf is not easily susceptible to corrosive agencies. Experiments have also been made which show that wood covered with a filler and three coats of spar varnish will take up approximately seventeeen grams per square foot of surface, when subjected to a humidity between ninety-five and one hundred per cent, and at a room temperature between seventy-five and eighty degrees Fahrenheit, while under'the same conditions th same kind of wood after having been treated in accordance with my invention will take up only approximately four tenths of a gram per square foot of surface.

It is to be understood that this invention is not limited ,to the treatment of propeller blades, but other materials may be treated in the manner above described within the spirit and scope of my invention as claimed.

What I claim is:

1. The herein described process of treating wood which consists in applying a coat of varnish to the wood to betreated, coating the entire varnished surface with metal leaf, and applying a coat of varnish to the metal surface.

2. The herein described process of treating wood that consists inapplying a coat of moisture repellant liquid to the wood to be treated, coatingthe ntire surface with metal leaf and applying another coat of liquid on the metal surface.

3. The herein described process of treating wood which consists in applying a filler to the wood to be treated to provide a smooth surface, impregnating the. surface with a li uid composition, affixing metal leaf aboiq: said surface, and lastly applying a coat 0 liquid to the metal leaf. i

4. The herein described process of trea'ting wood which consists in applying a filler to the wood to provide a smooth surface, coating the surface with a liquid composition, sizing th surface, aiiixing a metal leaf to the surface before the liquid thereon is dried, and then applying a coat of liquid to the metal leaf.

5. The herein described process of treating wood which consists in applying a filler to the wood to provide a'smooth surface, coating the surface with varnish, sizing of the surface, aflixing" metal leaf to said surface to seal the wood against moisture, and

. applying a coat of varnish to the metal surface. a

In testimony whereof I afiix my signature.

MATTHEW E. DUNLAP. 

